Permitting a user to interact with a device or an application running on a device is useful in many different settings. For example, keyboards, mice, and joysticks are often included with electronic systems to enable a user to input data, manipulate data, and cause a processor of the system to execute a variety of other actions. Increasingly, however, touch-based input devices, such as keyboards, mice, and joysticks, are being replaced by, or supplemented with devices that permit touch-free user interaction. For example, a system may include an image sensor to capture images of a user, including, for example, a user's hand and/or fingers. A processor may be configured to receive such images and initiate actions based on touch-free gestures performed by the user. It is desirable to improve upon techniques for detecting and inputting touch-free gestures.